System and method for communication with an infusion device

ABSTRACT

It may desirable to monitor or control a pump remotely. For example, the pump may be positioned near the patient, with remote control or monitoring of the pump occurring in a control room. In one exemplary embodiment, the pump is used in an MRI environment. In another exemplary embodiment, the pump is used in a hyperbaric chamber. The pump may monitor one or more physiological parameters and transmit them to the remote. The pump may also transmit information relating to the pump&#39;s operation. The pump may send the device and/or physiological data using one or more packets. The packets may consist of low priority sequential packets and high-priority asynchronous packets. The high-priority packets may enable the real-time monitoring of a patient&#39;s heart beat or other physiological parameter.

RELATED APPLICATIONS

This application is related to, and claims the benefit of U.S.Provisional 60/949,812 filed Jul. 13, 2007, the entirety of which ishereby incorporated by reference herein and made a part of the presentspecification.

FIELD OF THE INVENTION

This invention relates to a system and method for remotely communicatingwith an infusion device.

BACKGROUND

It is desirable to control the intravenous (IV) administration ofliquids to a patient. Frequently, patients scheduled for MRI examinationarrive with IV solutions being administered and controlled by deviceswhich must be disconnected as the patient is moved into the suite wherehigh magnetic fields are present and no outside RF interference can betolerated. Patients receiving hyperbaric chamber treatments may alsoneed administration of IV solutions. Hyperbaric chambers may treatmultiple patients at a time, and it is undesirable to stop hyperbarictreatment if a change in the administration of IV solution is needed.

SUMMARY

It may desirable to monitor or control a pump remotely. For example, thepump may be positioned near the patient, with remote control ormonitoring of the pump occurring in a control room. In one exemplaryembodiment, the pump is used in an MRI environment. In another exemplaryembodiment, the pump is used in a hyperbaric chamber.

In one embodiment, the remote utilizes controls that mirror the controlslocated on the pump. For example, the remote controls may include thestart or stop of fluid flow, silence of alarms, or setting or titratinga fluid delivery rate or volume. It should be understood that thecontrols on the remote are not necessarily coextensive with the controlson the pump.

In one embodiment, the display on the remote may also mirror the displaylocated on the pump. For example, the remote may display alarmconditions or the status of the battery at the pump. Again, theinformation displayed on the remote is not necessarily coextensive withthe information displayed on the pump.

In one embodiment, controls at the remote and the pump may be operatedsimultaneously.

In one embodiment, the remote acts as a charger for a spare pumpbattery. The charge status of the spare battery may be displayed by theremote.

In one embodiment, a side car module is attached to the pump to providea second channel for infusion delivery. The remote allows forcontrolling both channels.

In one embodiment, the pump operates without the remote or ifcommunication between the remote and the pump is interrupted. Displayson the pump and remote may indicate the connection status and relativesignal level. The remote may provide an alarm if the connection isinterrupted.

In one embodiment, the remote uses selectable communication channels.For example, a remote may be used to communicate with more than onepump. Similarly, multiple remote/pump pairings may be used in the samevicinity.

In one embodiment, the infusion device includes an ultrasonic motor thateliminates magnetic materials and that does not produce any detrimentalmagnetic fields and that is not affected by external magnetic fields.The ultrasonic motor may drive a peristaltic or other suitable fluidpumping mechanism. The motor may be driven by a multiphasic electronicsignal with little RF harmonic noise in the spectral range of about 6 or8 MHz to about 130 MHz in which MRI receivers are most sensitive. Thedrive power for the ultrasonic motor is generated via circuitry whichproduces multiphasic drive signals of at least sine and cosine waveformsat related ultrasonic frequencies. These drive signals are produced as asinusoidal wave to reduce high frequency harmonic components which maydisturb RF responsiveness. One scheme for producing these multiphasicsignals uses coreless or “Air Core” transformers constructed withinherent leakage inductance that interacts with the complex impedance ofthe ultrasonic motor to convert lower voltage square wave signals at theprimary winding into sinusoidal high voltage signals at the secondarywindings suitable for powering the ultrasonic motor and producing littleharmonic RF interference. Alternatively, D.C. voltages of oppositepolarities can be alternately switched to supply alternating voltages.The switched signals can be filtered into sinusoidal signals and appliedto the inputs of high voltage linear amplifiers that are set for suchgain as needed to produce resultant outputs of sufficient voltage andsinusoidal shape to drive the ultrasonic motor.

Control electronics receive commands through an input keypad for settingprescribed fluid flow rates to be delivered, and such inputs aretranslated into signals to control the ultrasonic motor and pumpingmechanism. Various safety devices feed back operational information tothe control electronics, including detection of motor speed and motionof pump elements, air bubbles in the fluid path, drip rate, highpressure, low fluid, low/no flow, overtime, and the like. The presentinfusion device includes battery power for portability, and is housed inone RF-shielded, non-magnetic housing to prevent introducing imagedegrading RF interference or producing distortions of the homogeneousmagnetic field, and without being affected by the strong magnetic fieldsor RF energy produced by the MRI system.

In one embodiment, the infusion device may be configured to monitor oneor more physiological parameters of a patient. In one embodiment, theinfusion device may be configured to transmit information related to itsoperation. In one embodiment, the physiological parameter and/or deviceoperation information may be transmitted to a remote using a series ofpackets. In one embodiment, the packets may include a first category ofpackets sent in a prescribed sequence. In one embodiment, the firstcategory of packets is sent at predetermined intervals. In oneembodiment, the first category of packets has a guaranteed minimum rateof transmission. In one embodiment, the packets may also include asecond category of packets corresponding to high-priority data. In oneembodiment, the infusion device may be configured to interleave packetscontaining high-priority data into the prescribed sequence of categoryone packets. In one embodiment, the remote or controller receiving thepackets may utilize a checksum or other appropriate means to verify thepackets' integrity. In one embodiment, category two packets may be usedto enable substantially real-time monitoring of a patient's heart beat.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic showing multiple infusion devices used in anelectromagnetically shielded environment.

FIG. 2 illustrates exemplary patterns used in a frequency hopping spreadspectrum system.

FIG. 3 is a partial perspective view of an infusion device in accordancewith one embodiment.

FIG. 4 is a partial perspective view of one embodiment of a pumpingapparatus.

FIG. 5 is a block schematic diagram of the infusion device of FIG. 3.

FIG. 6 is a side view of a length of precision tubing.

FIG. 7 is an exploded top view of valve apparatus.

FIG. 8 is a top view of the valve apparatus of FIG. 7 in one operatingconfiguration.

FIG. 9 is a top view of the valve apparatus of FIG. 7 in anotheroperating configuration.

FIG. 10 is an exploded side view of operative components.

FIG. 11 is a partial side view of the embodiment of FIG. 10 inassembled, operational configuration.

FIG. 12 is a block schematic diagram illustrating operating components.

FIG. 13A is a chart illustrating typical flow rate through a linearperistaltic pump operating at constant speed.

FIG. 13B is a chart illustrating flow rate through a linear peristalticpump operating in compensated manner.

FIG. 14 is a schematic diagram of drive circuitry for a multiphasicultrasonic motor.

FIG. 15 is an exploded perspective view of a pump unit.

FIG. 16 is a partial sectional view of a gasket disposed between housingsegments.

FIG. 17 is a partial cross sectional view of annunciator lights.

FIG. 18 is a front view of the pump unit of FIG. 15.

FIG. 19 is an exemplary illustration of an information packet.

FIG. 20 is an exemplary illustration of the transmission of Category 1and Category 2 packets.

DETAILED DESCRIPTION

U.S. Pat. No. 7,553,295 entitled “Liquid Infusion Apparatus”, issued onJun. 30, 2009 by R. Susi, U.S. Pat. No. 7,404,809 entitled “Non-MagneticMedical Infusion Device”, issued on Jul. 29, 2008 by R. Susi, and U.S.Pat. No. 7,267,661 entitled “Non-Magnetic Medical Infusion Device”issued on Sep. 11, 2007 to R. Susi are incorporated herein in theirentireties by this reference thereto.

The basic characteristics of an infusion pump involve the delivery ofmedicinal or nutritional liquids, over time, into the venous system of aliving subject. IV fluids are pumped at pressures typically in the rangeof 0.2 to 10 PSI. The infusion device may include detection ofover-pressure and have an upper operational limit of about 20 PSI. Flowranges typical of IV pumps are from 0.1 to 2000 ml/hr. Thesespecifications are different from the specifications for injectordevices which are often used in radiologic settings for purposes ofrapid bolus injection of image-enhancing contrast agents. Such devices‘push’ contrast agents at pressures up to 300 PSI and in very shortperiods of time in contrast to IV drug delivery systems. Contrast agentsare for image enhancement and are commonly delivered using piston orsyringe-type pumps that provide the requisite high fluid pressures andrapid deliveries.

The high magnetic field surrounding MRI systems can negatively affectthe operation of various devices (including IV control devices),especially those devices that are constructed with magnetic materials,and can seriously jeopardize a patient's safety as a result of devicesutilizing magnetic materials that can be attracted at high velocity intothe magnetic field where patient or attendant personnel are located.

Devices for infusing liquids into a patient are often attached to an IVpole holding both the infusion device and associated liquids to beinfused. Such devices may utilize stepper-type motors or simple DCmotors which include magnetic materials for providing the mechanicalpower required to drive the pumping unit. Further, a control unitreceives inputs of prescribed infusion rate settings, and controls thepumping unit to deliver the desired quantity of liquid over time. Thecontrol unit may emit spurious radio frequency signals as a result ofpoor electrical design or insufficient shielding.

Medical devices intended to be used within the MRI environment needspecial consideration. RF stimulation of atomic nuclei within anassociated magnetic field results in the emission of a small RF spinecho from the nucleus so stimulated. In the case of patient imaging,hydrogen nuclei bound with water are the usual targets for magneticresonance at selected frequencies. Other molecules and compounds canalso be selected for study, as in Nuclear Magnetic Spectroscopy, bychoosing resonance specific magnetic field strengths and associatedradio frequencies. For simplicity the typical hydrogen atom-basedimage-acquisition process is referred to herein, but it should berecognized that the disclosure is equally useful in spectrographicstudies at a plurality of field strengths and frequencies.

Certain devices may be needed in the scan room either to assist withcare of the patient being imaged or for the use of attending staff. Ofparticular interest are those devices placed in the scan room during thetime of image acquisition when the patient is present and the magneticfields are up and RF reception of the tiny nuclear echoes must becleanly acquired. Electrically passive metallic items such as oxygenbottles or crash carts present safety hazards to the patient due totheir potential to be strongly attracted by the magnetic field of thescanner. Such items can be pulled into the imaging volume where thepatient is located, creating potential for serious injury or death.Additionally, great effort is made during the manufacture andinstallation of the scanner/magnet to assure that the lines of fluxwithin the imaging volume are highly homogenous to assure that acquiredimages have minimal spatial distortion. Thus, devices formed of magneticmaterial that are positioned within the magnetic field of the scannercan introduce distortions into this homogeneous field and the resultantimages. The level of hazard and the degree of field/image distortion dueto magnetic materials depends upon the composition and location withrespect to the imaging volume.

The hazards due to flying objects can be controlled to some degree bythe use of non-ferrous devices such as the aluminum oxygen bottle.Additionally, the gravitational weight of some devices or their rigidfixation in the scanning room may be sufficient to overcome the force ofmagnetic attraction on the ferrous mass of such devices toward theimaging volume. However, such devices with some ferrous mass, thoughinhibited from being pulled into the magnetic field, may neverthelessintroduce inhomogeneity in the magnetic field. Distortions in thehomogeneity of the magnetic field within the imaging volume must be keptat such a level as to be of minimal consequence to the operator readingthe resultant image or data. And, the possibility of field distortion isproportionally increased as devices with metallic materials arepositioned closer to the imaging volume, with the most critical positionbeing near the center of the imaging volume, essentially where thepatient is positioned. Additionally, because of the extremely low levelsof RF signals produced by the target image nuclei, great care must betaken to assure that devices with active electronic circuits do not emitspurious RF signals as forms of electronic noise. Such noise can sodegrade the signal-to-noise ratio of signals received by the sensorcoils and receivers that image resolution is reduced or renderedcompletely unreadable. Active circuits must be carefully shielded toassure that their RF emissions are extremely low at the specificfrequencies of the imaging process. Conversely, it is possible throughcareful design, to place a source of RF energy for signal transmission,therapy, or the like, within the MRI environment, but such signalsshould be chosen to avoid the discreet Lamar discrete Larmor frequenciesunique to the particular magnetic field strength of a given scanner, andshould be of such high spectral purity as to coexist without causing anydeleterious effects. The intense magnetic fields produced by the scannercan cause detrimental effects on the performance of common DC andstepper motors in devices needed within the scanning room, to the pointof making their control difficult or causing their complete failure. Thegradient or time-varying magnetic fields can induce changing (AC)currents in motors and associated circuitry which may also cause falsemotor operation.

An RF shielded room is often used to isolate an MRI system from externalsources of electromagnetic fields. The shielded room is designed tosignificantly attenuate electromagnetic fields under 130 MHz, as mostMRI systems operate from 4 MHz to 130 MHz. This shielding may result inthe attenuation of other frequency ranges that are not targeted, such as2.4 GHz signals used for wireless communication. Achieving −100 dBattenuation of targeted signals may inadvertently result in −70 to −80dB attenuation of signals in the 2.4 GHz range.

It is common to find medical facilities with multiple MR scanners in thesame vicinity, often sharing the same control room. It is desirable toprovide a remote control for the infusion pump that can be operated, forexample, from the control room. More than one infusion pump may be usedduring a scanning procedure, and it is possible that multiple infusionpumps may be operating at the same time. In one embodiment, allow remoteoperation of multiple pumps is accomplished by assigning each remote andpump pairing a communication channel.

FIG. 1 illustrates a medical facility with three shielded rooms in thesame vicinity. Each room has an infusion pump 10, 12, 14, and isseparated from the other rooms and the control room with electromagneticshielding 18. Each pump has a corresponding remote 20, 22, 24 that islocated in the control room. A strong signal 30, 34 is needed to passthrough the electromagnetic shielding 18, resulting in an attenuatedsignal 30 a, 34 a to communicate with the infusion pump 10, 14.Likewise, a strong signal from the pump is needed to pass throughshielding 18 to reach the remote control with minimal signal levelsneeded for reception. While FIG. 1 illustrates communication from theremote 20, 24 to the pump 10, 14, it is to be understood that there mayalso be communication from the pump 10, 14 to the remote 20, 24.

The pump's transceiver is located within the pump's shielded housingwhich keeps internal pump stray RF noise from reaching the MR imagingdetector coils and corrupting the images. However, the transceiversantenna should be mounted outside the pump units shielding package. Thefeed to this antenna should be high pass or band pass filtered so as toallow the 2.4 GHz signals to pass, but not allow image interfering lowerfrequency RF noise within the scanners frequencies of interest toescape.

In this embodiment, a separate remote for each infusion pump is used. Asa result, the control room has three remotes that are broadcastingstrong signals. The remotes 20, 22, 24 in the control room may establisha connection with the pumps 10, 12, 14 by transmitting a “hunting”packet. The remotes 20, 22, 24 receive hunting packets from neighboringremotes at full power, which may swamp or overload the receivercircuitry, which makes detection of the weaker signal from the pump verydifficult.

In one embodiment, a bi-directional frequency hopping spread spectrumradio link is used for communication between the pump 10, 12, 14 and theremote 20, 22, 24. To alleviate the problems caused by multiple remotesbroadcasting strong signals in the same vicinity, a different frequencyhopping pattern is used for different connections. Frequency hoppingspread spectrum transmissions are spread over a portion of the radiospectrum.

In one embodiment, a 2.4 GHz industrial, scientific and medical (ISM)radio band is used. In one implementation, frequencies are selected inthe range from 2.400 GHz to 2.482 GHz. Changing the order of hopsthrough the bands for different connections provides one way of reducingthe possibility of multiple devices broadcasting on the same frequencyslots in a way that prevents communication.

In one embodiment, the devices may operate utilizing a Bluetoothprotocol. The Bluetooth Core Specification version 2.1, available atwww.bluetooth.com, is incorporated herein by reference. In oneembodiment, the Bluetooth compatible devices may operate in a bandstretching from 2.400 GHz to 2.4835 GHz with a lower guard ban of 2 MHzand an upper guard ban of 3.5 MHz. In one embodiment, there may be 79available channels. In one embodiment, the frequencies of the availablechannels (in GHz) may be given by the equation f=2.402+k MHz where k=0,1, 2 . . . 78.

Changing the duration of time a frequency slot is used provides anotherway of reducing the possibility of multiple devices broadcasting on thesame frequency slots in a way that prevents communication. In oneembodiment, the duration of use of a frequency slot varies from 8 ms to18 ms. The duration should be long enough for the radio frequencysynthesizer to tune and stabilize at each hop, and then send the packetof data before hopping to the next frequency in the pattern. Usingdifferent hop times further reduces the likelihood of two differentpatterns overlapping.

FIG. 2 illustrates an example of using both frequency hopping andchanges in duration for a communication link. As illustrated, thefrequency can range from 2.400 GHz to 2.480 GHz. Segments 200, 202, 204represent communication over a first link, and segments 210, 212, 214represent communication over a second link.

In another embodiment, the hopping pattern can be limited to portions ofthe available bandwidth. For example, one communication link can beprogrammed to limit the hopping pattern to the lower end of a band (suchas 2.400 GHz to 2.435 GHz) and another communication link can be set tooperate at the higher end of a band (such as 2.450 GHz to 2.480 GHz).

It may also be desirable to restrict certain frequencies from beingused. For example, if neighboring devices cause interference atparticular frequencies, those frequencies can be excluded from thehopping pattern.

In one embodiment, different hopping patterns are presented to a user aschannels. The hopping pattern for a particular channel may use differentfrequency changing patterns, time duration patterns, and/or excludedfrequency patterns from another channel.

It should be understood that a remote can communicate with more than oneinfusion pump. In one embodiment, the remote allows for selection of achannel that coincides with a channel for a specific infusion pump. Inanother embodiment, the remote cycles through a plurality of channelsand provides periodic updates to the remote operator of the status ofthe infusion pump for one or more active channels.

For each channel, the frequency hopping pattern and time durationpattern could be configured by a user. Alternatively, the patterns couldbe predetermined. The predetermined patterns could be arranged to avoidconflicts with equipment known to be used in the vicinity or inconjunction with an infusion pump device in various scenarios, such asthe MRI environment.

A remote for an infusion pump has application in other areas as well.For example, the remote could be used with a hyperbaric chamber.Hyperbaric chambers provide a pressure greater than sea levelatmospheric pressure to an enclosed patient. There are several uses forhyperbaric chambers. For example, the direct pressure in the hyperbaricchamber may be used to treat decompression sickness by slowing thenitrogen release and reducing the size of gas bubbles. Pressurizedoxygen may be used to purge carbon monoxide from the body.Vasoconstriction can reduce compartment pressure, edema, swelling, andtheir consequences. The increased oxygen is bactericidal to anaerobicorganisms. In addition, increased oxygen stimulates white blood cells.

The hyperbaric chamber can be used for various purposes, and it is notuncommon to have multiple individuals in the same hyperbaric chamber.Once the chamber has been pressurized, it is inconvenient to interruptthe session, especially if multiple patients are in the chamber. Somepatients in the chamber may be connected to a liquid infusion device,which may need to be adjusted during the session. Allowing the liquidinfusion device to be controlled remotely alleviates the need tointerrupt a session if the settings need to be changed.

FIG. 3 illustrates one embodiment of a liquid infusion device 43 that isoperable within an electromagnetically shielded room or a hyperbaricchamber. The liquid infusion device 43 is also operable within intensemagnetic fields and with negligible RFI to provide positive displacementof a liquid 45 such as saline or antibiotics, or sedative, or the like,in controlled volumes per unit time. The device does not include anyferrous or magnetic materials, and is substantially shielded againstirradiating any RFI during operation. The device 43 includes a pump inthe lower chamber 47 that receives therein a flexible, resilient tubing49 that is pre-packaged and sterilized as a component of an IV liquidinfusion set. Drip chamber 51 is also part of the infusion set. Controlsfor the pump in chamber 47 include an operator's input keypad 48 that isshielded against radiation of RFI for setting infusion parameters, and adrip detector 52 that may be disposed about the drip chamber 51 todetect flow of liquid from the supply 45. A display 53 is positioned inthe housing 55 which may be formed of non-magnetic, RF-shieldingmaterial such as conductively-coated plastic or aluminum, or the like.The housing 55 attaches with, for example, clamps 57 to a rigid support59 formed of non-magnetic material such as fiberglass or aluminum, orthe like.

FIG. 4 illustrates a pump 406 and a corresponding remote control 408. Inthis embodiment, the remote utilizes controls that mirror the controlslocated on the pump. For example, the remote controls may include thestart or stop of fluid flow, silence of alarms, or setting or titratinga fluid delivery rate or volume. An alarm condition for the pump 406would also be indicated by the remote control 408. An infusion devicemay have dual pumps which can be controlled independently. In oneembodiment, a side car module is attached to the pump to provide asecond channel for infusion delivery. Each of the pumps may be fullycontrolled by the remote control 408. It should be understood that thecontrols on the remote are not necessarily coextensive with the controlson the pump.

In one embodiment, the display on the remote may also mirror the displaylocated on the pump. For example, the remote may display alarmconditions or the status of the battery at the pump. Again, theinformation displayed on the remote is not necessarily coextensive withthe information displayed on the pump.

In one embodiment, the remote acts as a charger for a spare pumpbattery. The charge status of the spare battery may be displayed by theremote.

One pump could be used to remotely control other pumps. For example, apump could be placed in the control room, and that pump would thencommunicate with pumps being used with a patient. In another embodiment,a pump that is being used with a patient could also be used to remotelycommunicate with a pump being used with a different patient.Accordingly, “remote” as used herein may refer to a device that is notphysically attached to a pump, although in some embodiments a remote maybe part of one pump that is used to control another pump.

In one embodiment, controls at the remote and the pump may be operatedsimultaneously. For example, an operator in the control room and anotheroperator near the patient may both adjust operation of the pump throughcontrols that are local to each operator. Changes in the display wouldbe communicated to both the operator in the control room and theoperator near the patient, so that both operators can see the effect ofthe others actions.

In one embodiment, the pump operates without the remote or ifcommunication between the remote and the pump is interrupted. Displayson the pump and remote may indicate the connection status and relativesignal level. The remote may provide an alarm if the connection isinterrupted.

In one embodiment, the remote uses selectable communication channels.For example, a remote may be used to communicate with more than onepump. Similarly, multiple remote/pump pairings may be used in the samevicinity.

Referring now to the pictorial block schematic diagram of FIG. 5, thereis shown a peristaltic-type positive-displacement pump 60 disposedwithin the pump chamber 47 of the housing 55 to operate with the lengthof tubing 49 that passes therethrough between the drip chamber 51 andthe patient. The peristaltic pump 60 (linear or rotational) is driven byan ultrasonic motor 64 via appropriate mechanical linkage 65 to actuatea squeeze roller against the tubing 49, or to actuate a series ofelements 67 through a linear tubing-squeezing sequence to produceperistaltic pumping action. Various visual and audible annunciators 61may be provided to signal operational conditions either withinacceptable limits, or within error or failure conditions.

An ultrasonic driving motor 64 is powered by multiphasic signals appliedthereto from the motor drive circuit 69. A controller 71 for the deviceincludes a central processing unit 73 with associated peripheralcomponents including Random Access Memory (RAM) 75, Read-Only Memory(ROM) 77, Digital-to-Analog (D/A) converter 79, and an Input/Outputchannel 81. This controller 71 receives input control information fromthe operator's keypad 48, and receives feedback information about pumpspeed and position from sensor 83 and about liquid flow from dripdetector 85 disposed about the drip chamber 51. In response to theinputs supplied thereto, the controller 71 operates on stored programsto actuate a display 53 of operating parameters (or other data), and toactuate the motor drive circuit 69 for energizing the ultrasonic motor64 for rotation at a controlled speed. A power supply 63 is connected tothe controller 71 and drive circuit 69 to supply electrical powerthereto, and is connected to a battery 87 to receive electrical powertherefrom during stand-alone operation, or to receive line voltage viaplug 63, as required.

In accordance with one embodiment, no magnetic material is used in anyof the components of the infusion device 43 including the ultrasonicmotor 64, pump 60, power supply 63, controller 71 and associatedcomponents. Additionally, none of such components is adversely affectedduring operation by a strong magnetic field. And, any RF energy that maybe generated by electronic signals within the ultrasonic motor 64, drivecircuit 69, controller 71, power supply 63 or associated components isspecifically shielded by conductive structures 91, 93 disposed aroundsuch components to inhibit radiation of RFI. Additionally,radio-frequency interference filters 95 are disposed about allthrough-shield conductors to inhibit radiation of RFI through suchportals.

Referring now to FIG. 6, aspects of the liquid-delivery systems inaccordance with one embodiment is shown. A liquid conduit 404 includes afluid connector 402 at an input or proximal end, and includes a flangedconnector 701 that couples the proximal segment of the liquid conduit404 to an intermediate segment including a length of precision tubing703 that terminates in flow valve 705. The assembly is prepared andsterilized and packaged in an hermetically-sealed envelope forinstallation in a pumping device 406, as needed to infuse liquid into apatient.

The precision tubing 703 may be formed as a thin-walled extrusion of aflexible, elastic material such as silicone rubber, or otherbiocompatible polymer that confines a selected liquid volume per unitlength within the bore of selected cross-sectional dimension between theflanged connector 701 and the flow valve 705. In this way, progressiveperistaltic pumping by successive pinching and advancing of the pinchpoint along the tubing 703 toward the flow valve 705 administers a knownvolume of liquid to a patient. The length of tubing 703 between flangedcoupling 701 and flow valve 705 may be slightly stretched into positionwithin the pumping device to provide resilient engagement of the flangedconnector 701 and flow valve 705 within their respective matingreceptacles 706, 708 disposed at opposite ends of the active peristalticpumping mechanism of the pumping device.

The flow valve 705, as illustrated in the exploded top view of FIG. 7,includes an outer housing 707 within which the precision tubing 703passes. The mating receptacle 708 in the pumping device for the housing707 includes a complementary recess that receives the housing 707 inonly one orientation and secures the properly-installed housing in placewith the aid of slight tension exerted thereon by tubing 703. A slide orshuttle element 710 is disposed within the housing 707 to slidelaterally relative to the elongated axis of the tubing 703, with thetubing 703 passing through a tapered aperture in the shuttle element710. Thus, with the shuttle element 710 fully depressed within thehousing 707, the tubing 703 passes through the portion of the apertureof maximum cross sectional dimension, leaving the bore of the tubing 703fully open for unimpeded flow of liquid therethrough. In alternateposition of the shuttle element 710 maximally protruding from thehousing 707, the tubing 703 is pinched within a portion of minimalcross-sectional dimension of the aperture, as shown, to inhibit liquidflow through the tubing 703. Thus, as initially installed within thepumping device, the flow valve 705 is configured to inhibit flow throughthe liquid conduit 404 to ensure no inadvertent dosing of a patientuntil the pumping device is rendered operational.

In accordance with one embodiment, the pumping device is inhibited fromadministering liquid to a patient until a liquid conduit 404 is properlyinstalled and an access door 407 is fully closed and safely latchedshut. The access door 407 carries passive components of interlockingelements that properly engage and interface with active components ofthe device 406 for proper operation only with the access door 407 fullyclosed and safely latched shut. The region of the device 406 that isaccessed through the opened access door 407 includes a generallyvertical channel for receiving the flanged connector 701 in acomplementary receptacle 706 that is positioned above the peristalticpumping mechanism 712. A sensor may be disposed above the receptacle forthe flanged connector to optically sense presence of liquid in theproximal portion of the conduit 404, and operate to inhibit the pumpingdevice 406 from further pumping activity in response to sensing an emptyconduit.

As illustrated in FIGS. 10 and 11, the access door 407 carries an upperplaten 716 that cooperates with a pressure sensor 717 disposed behind aflexible membrane 711 and intermediate the receptacle 706 for theflanged connector 701 and the peristaltic pumping mechanism 712 toposition an initial length of installed tubing 703 between spaced platen716 and pressure sensor 717. In this way, the pressure at which liquidis supplied to the device can be tonometrically determined within theprecision tubing 703, or otherwise measured, for use in correctingcalculation of pumping activity required to deliver a selectedvolumetric infusion rate of liquid to a patient.

Similarly, a platen 718 is carried on the access door 407 at a locationaligned with another pressure sensor 719 disposed intermediate thepumping mechanism 712 and the flow valve 705. In the manner, similar tooperation of pressure sensor 717, the pressure sensor 719 and platen 718confine the precision tubing 703 to provide tonometric measurement, orother measurement, of outlet pressure. An upper limit of outlet pressuremay be selected to trigger an alarm condition if such liquid outletpressure exceeds the set limit as an indication of a clogged outletconduit.

The access door 407 also carries a platen 721 positioned in alignmentwith the peristaltic pumping mechanism 712 to confine the precisiontubing 703 therebetween to effect linear peristaltic pumping activity inthe generally downward direction from inlet pressure sensor 717 towardoutlet pressure sensor 719. Neither pressure sensing nor pumpingactivity may proceed until the access door 407 is fully closed toposition the associated platens about the precision tubing 703 forproper sensing and pumping operations.

The access door 407 also carries a detent element 723 that mates with aresilient clamp 725 carried on the shuttle element 710 of flow valve705. Specifically, these mating elements effect sliding movement of theshuttle element 710 from initially protruding position (i.e., tubing 703pinched) toward fully open position (i.e., tubing 703 not pinched) asthe access door is closed, as illustrated in FIG. 8. Additionally, theengaged detent element 723 and resilient clamp 725 remain engaged as theaccess door 407 is initially opened, thereby to pull the shuttle element710 toward maximum protrusion from the housing 707 to pinch tubing 703and inhibit further liquid flow therethrough, as illustrated in FIG. 9.The attachment of the resilient clamp 725 carried on the shuttle element710 of flow valve 705, and the detent element 723 carried on the accessdoor 407 is overridden and resiliently released following maximumprotrusion of the shuttle element 710 and further opening of the accessdoor 407. Of course, detent element 723 may be carried on the shuttleelement 710, and a resilient clamp 725 may be carried on the access door407 to effect similar interaction and safety operation.

Referring to FIG. 10, an ultrasonic or optical sensor may be disposedwithin the device 406 at a location thereon below the flow valve 705 andabout the distal segment of the liquid conduit 404 to detect thepresence of air bubbles in an outlet conduit that is formed ofultrasonically or optically-transmissive material. This sensor mayinclude a protruding U-shaped receptacle for receiving the conduittherein and for supporting optical elements in the protruding arms ofthe receptable to sense bubbles in liquid passing therebetween in theoutlet flow of liquid within the conduit. A mating U-shaped element issupported on the access door in alignment with the U-shaped receptacleof the bubble detector to capture the liquid conduit 404 fully recessedtherein in order to fully close the access door 407.

Referring to the partial side view of FIG. 11, there is shown a partialside view of the components of FIG. 10 assembled into operationalconfiguration. Specifically, the access door 407 disposed in closedconfiguration positions the platens 716, 718, 721 on one side of theintermediate length of precision tubing 703 against the respectivesensors 717, 719 and pumping mechanism 712. The flow valve 705 isconfigured to open condition and liquid is pumped through the conduit404, 703 in response to rotation of the cam shaft 727 of the peristalticpumping device 712. In this manner, pinch points along the precisiontubing 703 progress downwardly as successive pump elements 729 of thepumping device 712 are manipulated by the rotating cam shaft 727 toprovide the peristaltic pumping action.

Referring now to FIG. 12, there is shown a block schematic diagram ofthe operational components of the fluid delivery system according to oneembodiment. The peristaltic pump includes pumping elements or fingers729 that are manipulated in a pumping sequence in response to rotationof the shaft 727. The output shaft of ultrasonic motor 800 is coupled tothe pump shaft 727 that carries an optical encoder disk 802. Opticalsensing elements 801, 802 detect peripheral marks and an index mark forproducing outputs indicative of disk position and speed of rotation. Inone embodiment, a light source transmits light through the peripheralmarks to optical sensing element 801, and the light source alsotransmits light through the index mark to optical sensing element 802.In one embodiment, the peripheral marks are spaced to generate 1,000optical pulses per revolution. In one embodiment, the index markgenerates one optical pulse per revolution. In another embodiment, aplurality of index marks may be configured in, for example, a gray codepattern. In a further embodiment, a single sensor is used to detect boththe peripheral marks and the index mark, where the index mark may bedistinguished, for example, by creating a longer optical pulse. Theseoutputs are supplied to the controller 71 that also receives controlsignals from manual-entry keyboard 48 and from pressure sensors 717,719, bubble detector 718 and access door safety switch 716. Thecontroller 71 generates multiphasic drive signals via drive circuit 69and, among other functions, controls the display 53, alarm indicators,and the like.

The linear peristaltic pump mechanism may provide a high degree ofcontrol in order to assure accuracy and linearity of fluid flow rate.The operating speed of the pump shaft is modulated to overcome flow-ratenon-linearities or discontinuities commonly experienced within aperistaltic pumping cycle, as illustrated in the chart of FIG. 13A, offluid flow rate over time at constant shaft speed. For this reason, thecontroller 71 uses signal information indicative of the location of pumpelements during the interval of a pumping cycle in order to determinerequisite speed modulation and when to apply the speed modulation duringa pumping cycle. FIG. 13A shows the uncompensated flow output of theperistaltic pump according to one embodiment operating at a very slowRPM rate, over slightly more than one revolution (one cycle of 12 pumpfingers) that takes about 31 minutes and delivers about 0.32 ml offluid. It should be noted that there exists a no-flow “dead band” ofapproximately 11 minutes in the 31 minute cycle, including a smalldiscontinuity. The discontinuity is dependent on very small mechanicaltolerances such as the lengths of the fingers, the perpendicularity ofthe platen to the fingers, and the likes which vary pump to pump.However, the long 11-minute dead band is very similar pump to pump.

Fine control of pump-flow characteristics is established utilizingmodulation of the rotational speed during each cycle of the peristalticmechanism. The resultant flow, as illustrated in the graph of FIG. 13Bresembles the smoothness and linearity of syringe-fine pumps, adesirable characteristic when infusing potent drugs or infusing smallpatients, i.e., babies.

Specifically, FIG. 13B shows the flow output of the pump resulting fromspeed ‘modulation’ applied to each rotation. The rotational speedmodulation is accomplished using, for example, 8 discrete differentspeeds of the motor and pump during the dead band interval. Toaccomplish such speed modulation for flow correction, the drive motor800 should be able to start and stop very quickly and in very smallangular displacement typically in the range from about 3 to about 10milliseconds, and within about 0.3 to about 0.9 degrees of arc. Theencoder 801, 802 outputs of index and 1000 pulses per revolutionindicate to the controller 71 the starting position of the dead band(index plus mechanical offset by number of pulses counted) forcompensation and the exact (i.e., the rotational distance as pulsescounted) to control timing and application of the discrete speeds. Aftercompensation is applied in this way, the flow output of the linearperistaltic pump is very linear in delivering very precise amounts offluid of about 1 ml/Hr. The lowest pump rate (1 ml/HR) is a basis forcompensation as at high speeds the dead band is inherently shorter andless consequential.

The optical encoder 801, 802 provides both fine and coarse outputindications of the disk position and speed of rotation. Specifically,one index mark is sensed to identify the exact angular position of thepump shaft 727, and numerous peripheral graticule marks (e.g., 1000about the periphery) provide fine indication of angular re-positioningof the shaft relative to the index mark. Of course, the frequency ofrecurrence of sensed graticule marks also indicates rotational orangular speed of shaft 727. Thus, the controller 71 receives controlsignals from the optical encoder 801, 802 that facilitate modulation ofmotor speed in the manner as described above to overcome discontinuitiesor anomalies in a selected flow rate of fluid through the peristalticpump as illustrated in FIG. 13B, during portions of the pump cycledriven by the ultrasonic motor 800.

In order to accomplish fine resolution of fluid flow rates through theperistaltic pump, the drive motor 800 should be able to start and stopvery rapidly, typically within the range of about 3 to 10 milliseconds.Quick starting and stopping is used with control signals from theprocessor which pulse drive the motor and therefore make it move in veryshort steps. It is this ability to pulse drive the motor in short burstsof movement that allows modulation of the speed down to very slow levelswhen low fluid flows are desired.

The driving ultrasonic signals are generated by the drive circuit 69 atabout 43 KHz with very low harmonic content in the range of about 6 or 8MHz to about 130 MHz within which MR scanners are sensitive to RFsignals. This is accomplished on the drive circuit 69, as shown in theschematic diagram of FIG. 14, using a shift-register type of counter 70that receives input from voltage-controlled oscillator 72 to generatehigh-voltage ultrasonic frequencies in sine and cosine relationship 74,76. Coreless or air core transformers 78, 80 are driven push-pullthrough field-effect power transistors that receive paired outputs fromthe register 70. The primary inductance (through the turns ratio) andthe leakage inductance of these transformers 78, 80 coact with thecharacteristic input capacitance 82, 84 of the ultrasonic motor 800 toproduce substantially sinusoidal, high-voltage drive signals 74, 76 oflow harmonic content. These sinusoidal drive signals also passefficiently through the filters 95 from the electrically shieldedcontroller section 86 to the electrically shielded motor section 88, andexhibit concomitant low to negligible RF interference attributable todrive signal harmonics.

It should be noted that the ultrasonic motor 800 provides an AC signal90 representative of the composite sine and cosine drive signals. ThisAC signal 90 is rectified and integrated or low-pass filtered to producea DC voltage level 92 that is indicative of motor speed, and isdistinguishable from the position and rotational speed indicationsdigitally derived from the optical encoder 801, 802. The analog DCvoltage level 92 is applied via the operational amplifier 98 to thevoltage-controlled oscillator 72 in order to control the frequency ofthe motor drive signals. Specifically, the rotational speed of theultrasonic motor 800 varies inversely with frequency of the drivesignals. Accordingly, an applied ‘motor run’ signal 94 in combinationwith the DC feedback voltage 92 and the time constant of the R and Cfilter 96, cause the drive circuit 69 to generate drive signals 74, 76that sweep in frequency from a slightly higher initial frequency that isuseful for starting the motor 800 from standstill to an appropriaterunning frequency that establishes a steady-state motor speed.

Alternatively, the drive signals, 74, 76 for the ultrasonic motor 800may be generated from combined signals Q1/Q3, and Q2/Q4 through suitablefiltering to generate low voltage sinusoidal sine and cosine signals.These signals may then be amplified to sufficient level (typically about100 Volts RMS) to drive the ultrasonic motor 800.

Referring now to FIG. 15, there is shown an exploded perspective view ofone embodiment of the pump unit 406 in which a gasket 806 is disposedbetween mating segments 805, 807 of the housing. The gasket 806 isformed of a flexible and electrically conductive material to form afluid-tight seal between the housing segments 805, 807 as shown in thesectional view of FIG. 16. The conductive gasket 806 also inhibitsinternally-generated RF noise signals from radiating out of theconductive housing segments 805, 807. The conductive housing segments805, 807 thus form an integral shield that prevents radiative electronicsignals from emanating from internal circuitry, for example asillustrated in FIG. 12, and additionally protects such internalcircuitry from fluid spills that might be detrimental to reliableoperation.

Referring now to the sectional view of FIG. 17, there is shown one lightsource such as light-emitting diode 804 of a plurality of such lightsources and different colors that are lineally disposed within thehousing segment 805 near a top edge thereof. These light sources arepositioned behind the door 711 of conductive material that is hinged 730along an outer edge of the housing segment 805 to facilitate easy accessto the peristaltic pumping structure that is supported therein. The door711 includes a locking lever 733 for securely closing the door 711 inoperational position against a length of tubing 703, as illustrated andpreviously described herein with reference to FIG. 7. The door 711 alsoincludes a clear or translucent window 810, as illustrated in FIGS. 17,18, in alignment with the light sources 804 to provide large-areaillumination for easy visualization from a distant location of the lightfrom a source 804. A light-scattering element or light pipe 812 may bedisposed intermediate the light sources 804 and the window 810 toprovide more uniform illumination over the area of the window 810. Thus,a light source 804 of green color may pulse on and off recurring duringnormal pumping operation, and a light source of red color may pulse onand off recurring to indicate an alarm condition, all for convenientvisualization from a distant location. And the light sources 804 aresufficiently recessed within the conductive housing segment 805 toinhibit radiative RF noise signals from emanating from the housing.

Therefore, the liquid infusion apparatus promotes easy replacement orsubstitution of pumping devices without interrupting patient connectionor otherwise comprising sterility of an installed infusion system. Aninfusion set includes integral segments of a liquid conduit and operablecomponents for interaction and operational engagement with associatedcomponents of a pumping device that is compatible with an MRIenvironment. Ultrasonic motor drive signals are generated with lowharmonic content using efficient step-up transformer that co-act withthe characteristic input impedance of the ultrasonic motor to shapesignals as sinusoidal waveforms of low harmonic content.

In certain embodiments, physiological parameters of a patient may bemonitored. Such parameters may include for example, heart rate,respiration rate, blood pressure, blood oxygen saturation, eye responseto stimulation and the like. Conventional devices for monitoring theseparameters may need to be disconnected as the patient is moved into theMRI suite or hyperbaric chamber. Thus, it may be desirable to integratethese patient monitoring capabilities with a liquid infusion devicecompatible with an MRI suite and/or hyperbaric chamber.

In certain embodiments, the liquid infusion device 43 may transmitinformation related to its operation. Such information may includewithout limitation, pump pressure, current infusion rate settings,current actual or detected infusion rate, general status information,alarm conditions, amount of liquid infused, amount of liquid remainingto be infused, battery power, detected signal strength, and the like.Some or all of this information may be transmitted automatically in acontinuous fashion and/or in response to queries received from thecontroller. The information may be transmitted in a series of packets.The series of packets may follow a prescribed sequence. For example, afirst packet may transmit information related to the current infusionrate. A second packet may transmit information related to an amount ofliquid infused and so on. The complete series may repeat following aprescribed interval and may be completed for example once per second.Alternatively, the series of packets may be asynchronous.

The liquid infusion device 43 may also transmit information related toone or more physiological parameters as described above. In certainembodiments, one or more high priority physiological parameters may betransmitted with greater frequency than other low priority physiologicalparameters and/or with greater frequency than the device operationinformation described above. In certain embodiments, physiologicalparameter data that is anomalous or indicates a potentially dangeroushealth situation may be sent with greater priority. Physiologicalparameter data may be classified as high priority when it falls above orbelow predetermined thresholds or when it has experienced a rapidchange. For example, a physician may wish to monitor a patient's heartbeat in substantially real time, e.g., by receiving an audio or visualsignal corresponding to each heart beat as it is detected. This may beaccomplished by including heart beat information in each packet or in ahigh percentage of packets. In certain embodiments, each packet willcontain a dedicated one or more bits corresponding to heart beat. If aheart beat is currently detected as occurring, the one or more bits maybe set to ‘1’. If no heart beat is currently detected, the one or morebits may be set to ‘0’. Such substantially real-time monitoring may alsobe accomplished by generating a new packet when a heart beat isdetected.

As disclosed above, in certain embodiments device and/or physiologicalparameter data may be sent using packets. The data may be placed insidea packet and sent to the remote. When the remote receives the packet itmay determine the packet's validity and the packet's type, and thenprocess the packet data. In certain embodiments, an information packetmay contain one or more of the following components: a data component(which may contain, e.g., device data or physiological parameter data),a start token, a packet ‘type’ indicator token, a packet number, and achecksum component. FIG. 19 illustrates an exemplary embodiment of aninformation packet 500 with a data component 502 having three bytes. Inthis exemplary embodiment, the start token 504, packet ‘type’ indicatortoken 506, packet number 508, and checksum component 510 may each be asingle byte. In certain embodiments, more or less storage may beutilized for various components. In certain embodiments, the infusiondevice 43 may send information using two different categories ofpackets. A first packet category (category 1) may be used to sendinformation in a continuous or deterministic stream. In this embodiment,each packet may be assigned an identifier such as a numeric value thatindicates that packet's content type. In certain embodiments, the packettypes may be identified by numbers starting at 0 and ending at packetN−1, where N is the total number of packet types. In certainembodiments, 61 packet types may be used. In other embodiments, 5 orfewer packet types may be used. In other embodiments, between 6 and 60packet types may be used. In other embodiments, more than 61 packettypes may be used. The remote may be able to predict the packet that itshould receive next based on the previous packet's number.

When the pump sends packets to a remote, the pump will send packet type0, then packet type 1, and so on until the last packet is sent. Theprocess may repeat itself while the infusion pump is running. Packetsmay also be sent while the infusion pump is not running. Differentsequences of packets may be used for various configurations or operatingconditions, such as when the infusion pump is operating, when theinfusion pump is not operating, or when different physiologicalparameters are being monitored. Packets may be sent at a guaranteedminimum rate of R_(m) packets/second (e.g., R_(m)=30 for 30 packets asecond.) Packets may be sent faster than the guaranteed minimum rate.When a guaranteed minimum rate of transmission is used, all data at theremote is guaranteed to be completely updated in N/R_(m) seconds, orwhen 61 packet types are used, in just over 2 seconds.

When the communication link is compromised, packets begin to be missedand/or contain errors. The remote may determine the validity of a packetby using a checksum operation. One type of checksum operates by addingup the basic components of a message or packet, e.g. the asserted bits,and storing them. The remote or controller receiving the packet performsthe same operation on the data and compares the result to the authenticchecksum. If the sums match, the remote assumes that the packet was mostlikely not corrupted. More sophisticated types of redundancy checks thatmay be used include Fletcher's checksum, Adler-32, and cyclic redundancychecks. Other methods for error detection and/or correction may also beused, such as forward error correcting algorithms and/or turbo coding,automatic repeat request algorithms, Hamming codes, and the like. “Lost”packets may be detected by including a packet number with each packetand sending them in a prescribed sequence. If the remote receives apacket that appears to be out of sequence, e.g. if the remote receivespacket number 7 immediately after receiving packet number 5, the remotecan determine that the intervening packet was lost.

In certain embodiments, the receiver simply ignores lost or corruptedpackets until good packets (e.g. packets passing the checksum or otherintegrity test) are again received. In other words, the remote maysimply wait for the next packet rather than requesting that the missedor corrupted packet be resent. Alternatively, the remote may send asignal to the infusion device 43 requesting that the missed or corruptedpacket be resent. In certain embodiments, the infusion device 43 mayonly request that high-priority packets be resent. If the second attemptalso fails, the liquid infusion device 43 may again attempt to resendthe packet of high priority data. In certain embodiments, this processmay be repeated until a predetermined maximum number of attempts arereached. In certain embodiments, if a certain number of failed attemptsare detected, the remote may generate an alarm indicating a problem withthe wireless communication.

In certain embodiments, the system may provide a signal integrityindicator. The signal integrity indicator may display an indication ofthe detected signal strength by, for example, using a plurality of barssimilar to those used for cell phones or a number corresponding tosignal strength. When packets begin to get lost, the indicator mayindicate less signal strength. When the level of bad or lost packetsreaches a defined point, the indicator may indicate a “broken” link. Thelink may be classified as broken when the same packet is missed two orthree times in a row. In addition, or alternatively, the link may beclassified as broken when a certain number or percentage of the combinedpackets are missed within a predetermined period of time. The receiverwill constantly look for “good” packets and will “re-link” when goodpackets are again received.

One type of packet may indicate received signal strength information.For example, a packet may have been received correctly, but the signalstrength may be low. A packet may be sent indicating that one or morepackets were not received correctly or that the received signal strengthwas low. The received signal strength can be displayed. When a componentreceives a packet that indicates the received signal strength is low,the component may boost transmission power for future packets.Alternatively, when a component receives a packet indicating highreceived signal strength, the component may reduce the broadcaststrength of future transmissions.

As disclosed above, it may be desirable to send certain information withlittle delay, and without waiting for a certain packet or for a specificNth packet's transmission time. Such high priority data can includealarm sounds or messages, new data entered by the operator, detection ofa physiological event such as a heart beat, or the state ofindicator/status lights such as those corresponding to a patient'sreal-time heart beat. This information may be sent using a second classof packets (category 2). When these category 2 packets are queued-up tobe sent, they are given priority over the sequential, category 1packets. The transmitter can interleave category 2 packets into thesequential category 1 packets in a substantially immediate manner. Theinterleaved stream may send one or more category 2 packets between eachof the category 1 packets. However, in embodiments with a guaranteedtransmission rate, the category 1 packets will not be sent slower thanthe guaranteed minimum rate of R_(m) packets/second. Category 2 packetsmay include a special token or identifier to indicate their status ascategory 2 packets. Packet types may still be used in category 2 packetsto define the data contained.

FIG. 20 illustrates an exemplary transmission sequence of category 1 andcategory 2 packets. As illustrated, each of the packets 512, 514, 516,518, and 520 includes a packet number. As described above, the packetnumbers may be sequential to assist the remote in ensuring that nopackets are lost or corrupted. Three of the illustrated packets 512,516, and 522 are category 1 packets. A packet's category may beidentified by a separate category identifier. Alternatively, a packet'scategory may be embedded in or derived from the packet type identifier.The category 1 packets follow a prescribed sequence. Thus, packet 512 isidentified as a “type Y” packet. Packets 516 and 522 are identified as“type Y+1” and “type Y+2” packets, respectively, indicating adeterministic sequence. Interleaved between the category 1 packets areexemplary category 2 packets, 514, 518, and 520. The category 2 packetsdo not necessarily follow a prescribed sequence and may be generated andtransmitted as the need arises. Accordingly the illustrated category 2packets' types are identified by letters ‘J’, ‘Q’, and ‘L’, signifyingthe lack of a predefined sequence.

Category 2 packets may be particularly useful where it is desired tomonitor a physiological parameter such as a patient's heartbeat insubstantially real-time. For example, if the heart rate is 240 beats perminute or 4 beats per second, 8 category 2 “beep” packets should be sentevery 2 seconds. Accordingly, if there are 61 category 1 packets to besent, the “beep” packets would need to be placed in between every 7^(th)to 8^(th) category 1 packet.

If there is an urgency for transmitting a category 2 packet, thetransmission of a category 1 packet could be interrupted, and theinterrupted category 1 packet would then be retransmitted after thetransmission of the category 2 packet was complete. Alternatively,transmission of the category 2 packet could wait until the transmissionis complete for any active category 1 packet. If transmission of thecategory 2 packet is less urgent, additional category 1 packets could betransmitted prior to the transmission of the category 2 packet.Accordingly, the time required for transmission of a category 2 packetafter a triggering event could vary.

For example, the use of category 2 packets may allow a signal indicativeof a heart beat to be received by the remote within the time required totransmit the category 2 packet, within the time required to transmit theremainder of a category 1 packet and the category 2 packet, or withinthe time required to transmit a complete category 1 packet in additionto the remainder of a category 1 packet and the category 2 packet.

In another embodiment, a category 2 packet could be scheduled to followa particular category 1 packet. Similarly, a category 1 packet could beoptional, and may not be transmitted with every sequence.

Given the various embodiments available, category 2 packets may bescheduled, for example, within one second of a triggering event, withinhalf a second of a triggering event, within a tenth of a second of atriggering event, or within one one-hundredth of a second of atriggering event. These times are merely exemplary, and other responsetimes are also possible.

Although these inventions have been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present inventions extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the inventions and obvious modifications and equivalentsthereof. In addition, while several variations of the inventions havebeen shown and described in detail, other modifications, which arewithin the scope of these inventions, will be readily apparent to thoseof skill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments can be made and still fall within thescope of the inventions. It should be understood that various featuresand aspects of the disclosed embodiments can be combined with orsubstituted for one another in order to form varying modes of thedisclosed inventions. Thus, it is intended that the scope of at leastsome of the present inventions herein disclosed should not be limited bythe particular disclosed embodiments described above.

1. A remotely-monitored liquid infusion apparatus, comprising: a liquidconduit; a pump disposed within a housing to receive the liquid conduitand to transfer a liquid from a liquid source through the liquid conduitin response to activation of the pump; a wireless radio wave transceiverdisposed within an RF-shielded portion of the housing; a sensorconfigured to provide physiological monitoring of at least one of aheart beat, respiration and blood pressure, wherein the wireless radiowave transceiver is configured to wirelessly transmit, to a remote,high-priority data comprising information corresponding to theoccurrence of a physiological event and low-priority data comprisinginformation corresponding to operation of the liquid infusion apparatus,wherein the wireless radio wave transceiver receives, from the remote,data used to control operation of the pump, wherein the data used tocontrol operation of the pump is provided to a pump controller disposedwithin the RF-shielded portion of the housing, wherein the wirelessradio wave transceiver is configured to transmit the low-priority datain packets that are scheduled to be transmitted in substantiallysequential order and to transmit the high-priority data in packets thatare scheduled to be transmitted shortly after the occurrence of aphysiological event, wherein transmission of the high-priority data maytemporarily interrupt the substantially sequential transmission of thelow-priority data, wherein the RF-shielded portion is configured to passhigher frequency RF signals used for wireless communication whileattenuating image-interfering RF signals having a frequency under about130 MHz, and further wherein the wireless radio wave transceiver is incommunication with an antenna mounted outside the RF-shielded portion ofthe housing.
 2. The liquid infusion apparatus of claim 1, wherein saidsensor is configured to provide physiological monitoring insubstantially real-time.
 3. The liquid infusion apparatus of claim 1,wherein said wireless radio wave transceiver is configured to transmitat a guaranteed transmission rate.
 4. The liquid infusion apparatus ofclaim 1, wherein said remote is configured to verify the integrity ofreceived packets.
 5. The liquid infusion apparatus of claim 4, whereinsaid remote comprises a signal integrity meter.
 6. The liquid infusionapparatus of claim 1, wherein the liquid infusion apparatus isconfigured to be positioned within an RF shielded room having operatingRF-sensitive magnetic resonance imaging (MRI) equipment withoutinterfering with images captured by the MRI equipment and wherein theremote is configured to be positioned external to the RF shielded room.7. The liquid infusion apparatus of claim 1, further comprising a filterbetween the antenna and the wireless radio wave transceiver to inhibitthe image interfering lower frequency RF noise having a frequency belowabout 130 MHz from escaping the shielded housing.
 8. The liquid infusionapparatus of claim 1, wherein the data from the remote used to controloperation of the pump comprises data used to control the start or stopof fluid flow.
 9. The liquid infusion apparatus of claim 1, wherein thedata from the remote used to control operation of the pump comprisesdata used to control the silence of alarms.
 10. The liquid infusionapparatus of claim 1, wherein the data from the remote used to controloperation of the pump comprises data used to control the setting of afluid delivery rate or volume.
 11. The liquid infusion apparatus ofclaim 1, wherein the high-priority data transmitted to the remotecomprises data indicative of alarm conditions.
 12. The liquid infusionapparatus of claim 1, wherein the data transmitted to the remotecorresponding to an operation of the liquid infusion apparatus comprisesdata indicative of a status of a battery at the pump.
 13. The liquidinfusion apparatus of claim 1, wherein a feed to the antenna comprises afilter that passes the higher frequency wireless communication signals,and wherein the higher frequency wireless communication signals are inthe frequency range of 2.400 GHz to 2.480 GHz.
 14. The liquid infusionapparatus of claim 1, wherein said physiological event comprises arespiratory event.
 15. The liquid infusion apparatus of claim 1, whereinsaid physiological event comprises an anomalous event or an event thatis indicative of a potentially dangerous health situation.
 16. Theliquid infusion apparatus of claim 1, wherein said high-priority data isscheduled to be transmitted within half a second after the occurrence ofthe physiological event.
 17. The liquid infusion apparatus of claim 1,wherein said high-priority data is scheduled to be transmitted within atenth of a second after the occurrence of the physiological event. 18.The liquid infusion apparatus of claim 1, wherein said sensor is furtherconfigured to provide physiological monitoring of heart rate and bloodoxygen saturation.
 19. The liquid infusion apparatus of claim 1, whereinsaid low-priority data further comprises lower-priority physiologicalinformation.
 20. The liquid infusion apparatus of claim 1, wherein thewireless radio wave transceiver is configured to transmit at atransmission rate of at least 30 packets per second.
 21. A system,comprising: an IV infusion pump system configured to be positionedwithin an RF shielded room having operating RF-sensitive magneticresonance imaging (MRI) equipment without interfering with imagescaptured by the MRI equipment, the IV infusion pump system comprising: aliquid conduit, a pump disposed to receive the liquid conduit and totransfer a liquid from a liquid source through the liquid conduit inresponse to activation of the pump; a sensor configured to providephysiological monitoring of at least one of a heart beat, respirationand blood pressure; a wireless radio wave transceiver disposed within anRF-shielded portion of the IV infusion pump system; and an antenna incommunication with the wireless radio wave transceiver, wherein theantenna is mounted outside the RF-shielded portion of the IV infusionpump system; and a remote configured to communicate with the wirelessradio wave transceiver bi-directionally through RF shielding of the RFshielded room, wherein the wireless radio wave transceiver is configuredto transmit, to the remote, high-priority data comprising informationcorresponding to the occurrence of a physiological event andlow-priority data comprising information corresponding to operation ofthe IV infusion pump system, and wherein the wireless radio wavetransceiver receives, from the remote, data used to control operation ofthe pump, further wherein the data used to control operation of the pumpis provided to a pump controller disposed within the RF-shielded portionof the IV infusion pump system.
 22. The system of claim 21, wherein saidwireless radio wave transceiver is configured to transmit thelow-priority data in packets that are scheduled to be transmitted insubstantially sequential order and to transmit the high-priority data inpackets that are scheduled to be transmitted shortly after theoccurrence of the physiological event, wherein transmission of thehigh-priority data may temporarily interrupt the substantiallysequential transmission of the low-priority data.
 23. The system ofclaim 21, wherein the IV infusion pump system further comprises a filterconfigured to prevent image interfering lower frequency RF noise frombeing transmitted by the wireless radio wave transceiver.
 24. The systemof claim 23, wherein the image interfering lower frequency RF noise hasa frequency below about 130 MHz.
 25. The system of claim 21, wherein thewireless radio wave transceiver is configured to communicatebi-directionally with the remote in the presence of other RFtransmissions in the same frequency range.
 26. The system of claim 25,wherein the wireless radio wave transceiver is configured to communicatebi-directionally with the remote using a bi-directional frequencyhopping spread spectrum radio link.
 27. The system of claim 26, whereinan alarm occurs when there is a substantial interruption ofcommunication over the bi-directional frequency hopping spread spectrumradio link.
 28. The system of claim 21, wherein a feed to the antennacomprises a filter that passes wireless signals in the frequency rangeof 2.400 GHz to 2.480 GHz.
 29. The system of claim 21, wherein a feed tothe antenna comprises a filter configured to inhibit image interferinglower frequency RF noise having a frequency below about 130 MHz fromescaping the RF-shielded portion of the IV infusion pump system whilepassing signals at least in the frequency range of 2.400 GHz to 2.480GHz.
 30. The system of claim 21, wherein the physiological eventcomprises a heart beat or a respiration event.
 31. The system of claim21, wherein said physiological event comprises an anomalous event or anevent that is indicative of a potentially dangerous health situation.32. The system of claim 21, wherein said high-priority data is scheduledto be transmitted within half a second after the occurrence of thephysiological event.
 33. The system of claim 21, wherein saidhigh-priority data is scheduled to be transmitted within a tenth of asecond after the occurrence of the physiological event.
 34. The systemof claim 21, wherein said sensor is further configured to providephysiological monitoring of heart rate and blood oxygen saturation. 35.The system of claim 21, wherein said low-priority data compriseslower-priority physiological information.
 36. The system of claim 21,wherein the wireless radio wave transceiver is configured to transmit ata transmission rate of at least 30 packets per second.
 37. A system,comprising: an IV infusion pump system configured to be positionedwithin an RF shielded room having operating RF-sensitive magneticresonance imaging (MRI) equipment without interfering with imagescaptured by the MRI equipment, the IV infusion pump system comprising: aliquid conduit, a pump disposed within a housing to receive the liquidconduit and to transfer a liquid from a liquid source through the liquidconduit in response to activation of the pump; a sensor configured toprovide real-time monitoring of at least one physiological parameter ofa patient, wherein the at least one physiological parameter comprises atleast one of a heart beat, respiration, and blood pressure of thepatient; a wireless radio wave transceiver disposed within the housing,wherein the wireless radio wave transceiver is in communication with anantenna mounted outside the housing and a local system controllerdisposed within the housing, the local controller capable of receivinginput control information from the wireless radio wave transceiver andfrom input devices on the housing and configured to, upon execution ofstored instructions within the local system controller, output controlsignals to motor drive circuitry configured to operate the pump based,at least in part, on the received input control information; and awireless remote configured to communicate with the wireless radio wavetransceiver bi-directionally through RF shielding of the RF shieldedroom, wherein the local system controller operates in conjunction withthe remote, such that an operator can control the IV infusion pumpsystem liquid infusion apparatus either remotely or locally and suchthat the pump is capable of operating without the remote or ifcommunication between the remote and the pump is interrupted.